This invention relates to vibratory concrete screeds and in particular to a portable screed of minimum weight and optimal strength and stiffness which may be joined in a series of interconnected frame units to impart uniform vibrations to poured concrete for tamping and leveling of the concrete as it is finished.
As labor costs continue to escalate, it is becoming increasingly important to accomplish a labor-intensive task in the least possible time in order to incur the least possible labor expenses. To this end, and in particular with regard to finishing of concrete, various screeds have been developed in order to substantially reduce the period of time necessary to finish the concrete, yet at the same time enhance the surface appearance of the concrete.
One such screed is described in U.S. Pat. No. 4,030,873. This patent discloses a concrete screed having an open, truss-like framework which includes a central shaft which is flexible and which is loosely supported for rotation in bearings situated periodically along the length of the screed. A series of frame units can be joined to form an elongate screed for finishing of relatively wide expanses of poured concrete. Another type of screed, using compressed air to impart vibrations to the screed plates, is sold by the H. Compton Co., Conroe, Texas 77301. Like that disclosed in above-identified U.S. Pat. No. 4,030,873, the Compton screed is truss-like and may be assembled in a series of modular sections. A similar concrete screed is also manufactured by A.W.S. Manufacturing Inc., the assignee of the present invention.